Apparatus for component assembly



Jan. 24, 1967 B, BERGER APPARATUS FOR COMPONENT ASSEMBLY Filed Nov. 27, 1963 AMPLIFIER CONTACT DE TECTOR 8 COMMAND CENTER F/GZ R O T N E v W BERNARD A. BERGER MM @77 J ATTORNEYS United States Patent 3,299,494 APPARATUS FOR COMPONENT ASSEMBLY Bernard A. Berger, Montreal, Quebec, Canada, assignor to Northern Electric Company Limited, Montreal, Quebec, Canada Filed Nov. 27, 1963. Ser. No. 326,439

. 6 Claims. (Cl. 29-203) This invention relates to apparatus for accurately positioning components relative to each other and in particular for joining a cats whisker probe to a semi-conductor crystal in the manufacture of semi-conductor diodes.

In such apparatus it is necessary to apply a compressive 'ice The wedge flanks 9 and operate upon a bearing surface 11 of the arbor slide 7. 1

The wedge 8 is driven by rod 12, which connects the wedge with an industrial type double acting hydraulic cylinder 30 having an over pressure relief valve, and rod 12 is slidingly supported in a suitable journal 13.

force between the whisker and crystal so that the area of contact between whisker and crystal may be sufiiciently controlled to produce the desired electrical characteristics. This necessitates applying a compressive stress between whisker and crystal, which is conveniently achieved by continuing to advance the remote end of the whisker towards the crystal, past the point of initial contact, by a specific limited amount. My invention includes means to i:

After initial contact between crystal 3 and whisker 4 the further distance travelled by the driving wedge 8 is mechanically limited by stop assembly 15. This stop assembly 15 comprises a driving dog 16 fastened to the rod 12, for movement therewith as the wedge 8 is advanced or retracted by the hydraulic cylinder 30.

Movement of the actuator rod 12 towards arbor slide 7 causes driving dog 16 to contact a driven dog 17, mounted for purposes of rotation on an armature 18 of a magnetic brake arrangement. The axis of rotation, AA in FIGURE 2 of the armature 18, is arranged normal to the axis of advance of the actuator rod 12, sothat linear movement of the driving dog 16 attached to driving rod 12 will produce a corresponding rotary movement of the driven dog 17 about its axis AA, after the dogs 16 and 17 come into contact with each other.

A stop dog 19 is mounted for rotation about the same axis AA as the driven dog 17, being mounted however on a separate disc 20, comprising the body of thebrake v, arrangement, and having a limited arc of rotation between which I have found suitable is of disc-construction, electromagnetically operated.

I have found that control of the electromagnetic brake in a manner to produce the desired accuracy of contact between whisker and crystal can be carried out, using the whisker and crystal as a switch to close an electrical detector circuit. Energizatio-n of this detector circuit by the closing of the switch i.e. by initial contact between whisker and crystal, causes operation of the electromagnetic. brake.

The brake eflects coupling of a stop assembly to the wedge, whereby final travel of the wedge canbe closely controlled. The use of this stop assembly makes initial component positioning less critical.

In the drawings,

FIGURE 1 shows a diagrammatic arrangement of the apparatus;

FIGURE 2 shows a diagrammatic arrangement of the magnetic brake assembly and the associated stops.

Referring to FIGURE 1, the diode 1 is mounted for assembly in alignment with the driving arbor 6, the wedge 8 being in actuating contact with the arbor slide 7. The hydraulic actuator 30, is connected to the wedge 8 by rod 12. The stop assembly 15 associated with the driving rod 12 is powered through the amplifier 25, by signals from the detector 26.

In FIGURE 1 the diode housing assembly 1 includes a crystal pin 2 (usually of brass) on which a crystal 3 (usually of germanium) is mounted. The whisker 4 is shown in contact with the crystal 3. The whisker 4 is mounted on a whisker pin 5 (also usually of brass), the components being mounted within the walls 14 of the assembly 1.

Whisker pin 5 is drivingly secured in arbor 6, the arbor 6 being attached to a suitable slide 7 which is mounted for sliding along the axis of the whisker pin 5 by guides (not shown).

The driving wedge 8 has an initial advance flank 9 and a final advance flank 10, these flanks being set at diflerent angles to the axis of travel of the wedge S. The wedge 8 is suitably restrained, by means not shown, to slide in a direction generally normal to the axis of the whisker pin.

back stop 21 and adjustable stop 24. The body 20 carries a field coil (not shown) which is energizable to effect a magnetic coupling of the armature 18 to the body 20.

It can be seen from FIGURE 1 that with the magnetic brake elements de-energized the armature 18 is free to rotate, driven by contact between dogs 16 and 17 without producing any rotation of the body 20 and its associated stop dog 19. Energization of the brake produces an extremely rapid linking of armature 18 to the body 20, so that any rotary movement of the driven dog 17 subsequent to energization of the brake will produce a corresponding rotation of the stop dog 19.

The stop dog 19 is normally held against the back stop 21 by the return spring 22, but magnetic linking of armature 18 to body 20 with the dog 17 driven by the driving dog 16 then causes the stop dog 19 to rotate through the adjustable gap 23 until its further movement is prevented by the adjustable stop screw 24.

The arrest of stop dog 19 by the adjustable stop screw 24 prevents any further rotation of the driven dog 17, thereby causing the driving dog 16 to be halted, so that further advance of actuator rod 12 and the wedge 8 is thereby terminated, with a minimum of baclolash or impact effect. At this time the hydraulic cylinder relief valve is set to relieve excess hydraulic pressure to drain, so that the build-up of destructive forces in the driving rod 12 or stop assembly 15 is thereby prevented.

Actuation of the magnetic brake through its field coil in body 20 is obtained by means of an amplifier 25 which energizes the field coil through leads 28. The amplifier is activated at the moment of contact between the whisker 4 and the crystal 3. This contact completes an electrical circuit to a contact detector 26, which then provides an appropriate input to the amplifier 25 and thereby a-ctuates the magnetic brake assembly so that the driven dog 17 and stop dog 19 are effectively united to each other. It will be seen that appropriate adjustment of the stop screw 24 will effectively control subsequent travel of arbor 7 so that the reaction force exerted between the whisker 4 and the crystal 3 is correspondingly controlled. The accuracy of the joining operation and the corresponding quality of a joint so made is thereby closely controlled.

It is usual, at the time of completing the whisker-crystal contact, to pass a pulse through the circuit provided by contact detector 26, so that a junction is thereby achieved.

1 3 This is well known and does not form a part of this invention.

In view of the inherent non-overhauling characteristics of the wedge faces relative to the contact face 11 of slide 7, total relief of fluid pressure within the actuating hydraulic cylinder 30 does not permit automatic return of the wedge, because of its non-overhauling characteristic. In order that the arbor may be withdrawn by spring 27 operating on the slide 7 in a withdrawing direction, it is necessary for the driving rod to be actuated in a withdrawin-g direction to remove the wedge surface 10 from driving contact with arbor 7. This withdrawal of rod 12 may be carried out by reverse operation of the hydraulic actuator, or by means of a suitable spring such as spring 29 acting on the driven dog 17 of armature 18.

While this invention is disclosed in relation to the assembly of a particular electronic component, it is evident that the invention may be practiced by variations of the apparatus and for various purposes.

What I claim as my invention is:

1. Apparatus for bringing a first component and a second component int-o contact to produce limited reaction therebetween, comprising means for retaining the first component, means for mounting the second component for movement in the desired direction of contact, wedge means arranged transversely of the desired direction of movement, the mounting means for the second component having a face in contact with said wedge means, means to advancethe wedge means transversely of the said desired direction of movement of said second component and having a fluid actuator operative to move said wedge means, means to detect initial contact between said first and second components, a first stop member mounted for movement with said wedge means under the, influence of the fluid actuator, a second stop member movable between predetermined limits, and means selectively operable by said contact detecting means to move said second stop member between said predetermined limits in accordance with movement of said first stop member and said wedge means whereby the movement of the wedge means may be selectively limit-ed between said predetermined limits to produce a predetermined reaction force between said components.

2. Apparatus as set forth in claim 1, wherein the selectively operable means includes an electric brake operated by electrical contact between said first and said second components. I

3. Apparatus for joininga cats whisker member to a crystal member in the manufacture of a semi-conductor diode and comprising: means to fixedly mount one of the members to be joined, an arbor to position the other said member, a wedge for advancing said arbor towards said one member, a hydraulic actuator for advancing said wedge in a direction inclined to the direction of advance of said arbor, a rod drivingly connecting the hydraulic actuator to said wedge, a first stop means rigidly mounted on said rod for movement therewith, a second stop means rotatably mounted adjacent said rod and adapted to be driven by said first stop means, a third stop means mounted coaxially with said second stop means and having a limited arc of rotation, and brake means operable to link said sec-ond and said third stop means, whereby on operation of the said brake means to link said second and said third stop means, the subsequent advance of said first stop means and said rod is limited by the corresponding limited rotation of said third stop means.

4. Apparatus for bringing a first component and a second component into contact to roduce limited reaction therebetween, comprising means for retaining the first component, means for mounting the second component for movement in the desired direction of Contact, a wedge arranged transversely of the desired direction of movement, the mounting means for the second component having a face in contact with said wedge, means to advance the wedge transversely of the said desired direction of movement of said second compone nt, means to detect initial contact between said first and second components, a first stop member mounted for movement with said wedge under the influence of said wedge advancing means, a second stop member movable between predetermined limits, and means selectively operable by said contact detecting means to move said second stop member between said predetermined limits in accordance with movement of said first stop member andsaid wedge, whereby the movement of the wedge may be selectively limited between said predetermined limits to produce a predetermined reaction force between said components.

5. Apparatus for bringing a first component and a second component into contact to produce limited reaction therebetween, comprising means for retaining the first component, means for mounting the second component for movement in the desired direction of contact, means for driving said mounting means, means for detecting initial contact between said first and said second components; a first stop member movable in a predetermined path by said driving means in accordance with movement of said mounting means, a second stop member movable between predetermined limits, and means selectively operable by said contact detecting means upon said initial contact to move said second stop member between said predetermined limits in accordance with movement of said first stop member whereby the movement of said mounting means may be selectively limited between said predetermined limits so as to produce a predetermined compressive force between the components.

6. Apparatus as set forth in claim 5 wherein said selectively operable means includes an electrical brake operated by said contact detecting means.

References Cited by the Examiner UNITED STATES PATENTS 2,649,560 8/1953 Blair 29 25.3 X 2,651,207 9/1953 018011 74 2,757,440 8/1956 Carman 29 203 X JOHN F. CAMPBELL, Primary Examiner. WILLIAM I. BROOKS, Examiner. 

3. APPARATUS FOR JOINING A CAT''S WHISKER MEMBER TO A CRYSTAL MEMBER IN THE MANUFACTURE OF A SEMI-CONDUCTOR DIODE AND COMPRISING: MEANS TO FIXEDLY MOUNT ONE OF THE MEMBERS TO BE JOINED, AN ARBOR TO POSITION THE OTHER SAID MEMBER, A WEDGE FOR ADVANCING SAID ARBOR TOWARDS SAID ONE MEMBER, A HYDRAULIC ACTUATOR FOR ADVANCING SAID WEDGE IN A DIRECTION INCLINED TO THE DIRECTION OF ADVANCE OF SAID ARBOR, A ROD DRIVINGLY CONNECTING THE HYDRAULIC ACTUATOR TO SAID WEDGE, A FIRST STOP MEANS RIGIDLY MOUNTED ON SAID ROD FOR MOVEMENT THEREWITH, A SECOND STOP MEANS ROTATABLY MOUNTED ADJACENT SAID ROD AND ADAPTED TO BE DRIVEN BY SAID FIRST STOP MEANS, A THIRD STOP MEANS MOUNTED COAXIALLY WITH SAID SECOND STOP MEANS AND HAVING A LIMITED ARC OF ROTATION, AND BRAKE MEANS OPERABLE TO LINK SAID SECOND AND SAID THRID STOP MEANS, WHEREBY ON OPERATION OF THE SAID BRAKE MEANS TO LINK SAID SECOND AND SAID THIRD STOP MEANS, THE SUBSEQUENT ADVANCE OF SAID FIRST STOP MEANS AND SAID ROD IS LIMITED BY THE CORRESPONDING LIMITED ROTATION OF SAID THIRD STOP MEANS. 